Tubular metallic structures, pump housings, manifolds, and welded assemblies (collectively referred to as “tubular structures”) are commonly manufactured for use in a variety of applications, such as industrial machinery, automobiles, and aerospace applications. Newly fabricated tubular structures undergo a number of cleaning and testing phases before they are passed on for actual use. For instance, when a tube is used as a transport medium for liquids or gases, the inside of the tube must be cleaned to ensure that the inside of the tube is free of contaminants and debris that might contaminate the fluid being transported. When a tubular structure is to be used for transport of high-pressure fluids, the structure must be properly pressure tested to verify structural integrity prior to use.
The cleaning of the interior of tubes and similar components with relatively small diameter interior passages and those which include throughout their length a number of bent or curved portions, is especially difficult, primarily as the result of the difficulty of inserting conventional tools or other cleaning apparatus into the part and moving it along the full tube or interior passage length. A common technique for cleaning metal parts including the interior of tubes has been the use of so-called degreasing or vapor degreasing agents in which the parts are immersed in or exposed to a quantity of the cleaning liquid or vapor. This approach has been adopted extensively in the metal finishing industry.
Depending upon the ultimate use for the parts, the required cleanliness of the internal surfaces can vary considerably. In the case of gaseous oxygen or hydraulic lines used in aircraft or lines that carry liquid oxygen in missiles, for example, the tubes must be kept extremely clean and this requirement, of course, requires a more intensive cleaning operation. In the past, even when known highly efficient vapor degreasing agents were used, many hydraulic line tubing configurations had to be individually flushed with a solvent liquid in order to achieve the required high degree of cleanliness. As might be predicted, this resulted in a labor intensive and relatively expensive cleaning operation.
In addition to cleaning, proof pressure testing is used to verify the mechanical integrity of a fabricated structure. In typical pressure testing, the structure is filled with a type of fluid, either liquid (typically water) or gas (typically nitrogen), and pressurized to one and a half times the maximum operating pressure that the part is designed to operate with. The pressure is held for a period of time and then the pressure is released. The pressure cycle may be repeated multiple times as required to prove the structural integrity of the structure.
A typical pressure test system consists of a blast cell rated to contain the burst energy of the part being tested, a pump or accumulator to supply the required pressure, regulators and pressure gauges to regulate and measure the supplied pressure, relief valves to protect the system in the event of over pressurization, and various valves to direct and vent off pressure.
The processes of cleaning the various parts and pressure testing the various parts are both laborious and time consuming. In fact, in the mass production of tubular structures, cleaning and pressure testing are often the bottleneck in production schedules due to the need to set up special equipment for each task and the need to wait for equipment availability before each new part or set of parts may be cleaned or tested.
It is desired to provide a system and apparatus that would alleviate some of the problems associated with cleaning and pressure testing tubular structures. Particularly, it is desired to provide a system and apparatus that would reduce production time required to complete cleaning and pressure testing. Further, it is desired to provide a system and apparatus that would simplify the process steps required to clean and pressure test the tubular structures.